6F1F:
reference: BPTI folding revisited: switching a disulfide into methylene thioacetal reveals a previously hidden path., Mousa R, Lansky S, Shoham G, Metanis N, Chem Sci. 2018 May 2;9(21):4814-4820. doi: 10.1039/c8sc01110a. eCollection 2018, Jun 7. PMID: 29910933

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).